Self-energizing centrifugal clutches commonly have friction shoes which move outwardly against a drum on an output shaft responsive to centrifugal force resulting from powering an input shaft in a predetermined speed range. Springs cause the shoes to retract when the input shaft slows below a prescribed level. When the clutch is engaged vibration is transferred between the input and output shafts via the clutch and this is more pronounced when the shafts are not perfectly aligned.
Accordingly, there has been a need for a self-energizing clutch which will not transfer vibration between the driving and driven components, will not subject its parts to wear, and does not require precise alignment between its input and output rotary parts.
Couplers with a soft start characteristic require less power for startup because the full load is not coupled to the driving motor or other power source until the motor has accelerated to an adequate rotational velocity to take on the load. Although couplers such as disclosed in my prior U.S. Pat. No. 5,477,094 have soft start capabilities when properly matched with a load, there are instances where a still softer start is preferred while preserving the other advantages of the coupler.
The clutch of the present invention can have one or both of its rotor components provided with a sheave for a belt drive from a motor or other prime mover and/or a sheave for a belt drive to a load. The sheave arrangements are also applicable if the device is constantly a coupler, i.e., the magnets are always in an active position.